A. Field of the Invention
The invention relates to the field of curing lights that may be used to cure light activated composite materials. The preferred embodiment of the invented curing light system includes a light source that uses semiconductor lasers or light emitting diodes (LED's) to create light and an electronic control module. The system may be a portable hand-held unit that operates by battery power, or a non-portable unit that uses AC power from a standard wall socket.
More particularly, some preferred embodiments of the invention use light sources such as semiconductor lasers and light emitting diodes which can initiate curing of composite materials. Some of the more preferred embodiments of the invention include a light source that has a plurality of individual semiconductor diode laser chips or light emitting diode chips arranged on a single heat sink. In some embodiments of the invention, diode lasers or light emitting diodes may be arranged in an array on an appropriate base or fixture in order to provide greater light power. A housing for the heat sink and laser diode chips or light emitting diode chips may be provided, and the housing may include a light focus dome or a transparent window through which light travels before striking a composite material to be cured. When an array of laser or light emitting diode chips is used, a light with single or multiple wavelength can be achieved by placing the chips with different wavelength in the array. Thus, the light can be used to curing different composites with different photoinitiators.
Some preferred embodiments of the invention relate to a packaged laser or light emitting diode light source seated on a larger heat sink with electrode channels. In some embodiments of the invention, portion of light is a flexible fixture that may be bent in any desired direction for ease of use.
When the invention is used, light emitted from it can be directly applied to a curing surface without first traveling through a light guide, light focus means or fiber optics as used in prior art. Alternatively, a light guide, light focus means, fiber optics or other optics may be used with the system.
One preferred embodiment of the invention uses rechargeable DC batteries as a power source. That configuration facilitates portability. A battery charger is provided in that embodiment to charge the batteries and to power the system if it is desired to operate the system from a non-mobile power source. Another preferred embodiment of the invention is receives power from a cord attached to an AC power source outlet. Some of the more preferred embodiments of the invention include an electronic control module to control light output time and light intensity, and to monitor battery status.
B. The Background Art
In the prior art, various light sources have been used for the purpose of curing composite materials. Traditionally, the light source for a curing light is a filtered high power halogen, fluorescent, and arch lamps. A light guide is typically used to deliver the light to the surface of composite materials to be cured. That and other prior art is described below.
In U.S. Pat. No. 4,221,994 a curing light is disclosed which uses a fluorescent lamp to harden photosensitive reactants such as dental restorative material. U.S. Pat. No. 4,666,406 discloses a light guide for use in composite curing. U.S. Pat. No. 5,115,761 describes a chamber for curing adhesives. U.S. Pat. No. 5,415,543 discloses a curing light apparatus using an actinic light source with inert gas and a light guide. U.S. Pat. Nos. Des. 361,382 and Des. 385,630 disclose aesthetic designs for curing light systems. U.S. Pat. No. 5,616,141 discloses a laser system for use in dental procedures. U.S. Pat. No. 5,803,729 discloses a curing light system with a light guide that uses a light bulb with filtering.
The prior art described above suffers from several disadvantages: 1.) High power halogen lamps generate a large amount of heat. The heat might be transferred to a composite surface being cured, causing the material to deform. The heat can also cause discomfort to a patient if the curing light is being used in medicine or dentistry. 2.) Systems which generate large amounts of heat require a cooling system. Typically a cooling fan, gas coolant, or liquid coolant is used to dissipate generated in prior art curing light systems. A cooling fan creates substantial noise and is therefore undesirable. Gas and liquid coolant increase system size, weight, complexity and cost. 3.) Commercially viable prior art systems are large in size. 4.) Systems which use ordinary AC power rather than DC battery power tend to have greater circuit complexity and are not portable. (see Clinical Research Associates Newsletter Volume 10, June 1986, Volume 20, March 1996),
A portable curing light system using battery power and a filtered halogen light source has been marketed by L.D Caulk/Dentsply of Milford, Del. That system is relatively large in size and has some of the disadvantages listed above.
Solid-state lasers have been used as a light source for curing lights. For example, U.S. Pat. No. 5,616,141 discloses a curing light apparatus using argon ions as its light source. There are advantages to curing by use of laser light compared to curing by use of different lamps. Laser curing tends to be faster, generates less heat and provides superior characteristics in the cured composite. However, argon laser systems are disadvantageous compared to semiconductor laser systems because argon laser systems are large, need appropriate cooling devices, and are expensive to manufacture.(See Clinical Research Newsletter Volume 20, March 1996)
A curing light system that uses light emitting diodes as a light source is disclosed in U.S. Pat. No. 5,420,768. That system includes a packaged LED array and a light guide. The disclosure is vague and incomplete, however, in that no detailed description is provided concerning light source construction or the control system. Light emitting diodes have been used as light sources in other applications in the prior art. See, for example, U.S. Pat. Nos. Des. 395,051; 5,890,794; and 5,161,879.
Therefore the prior art has shown a need for a curing light for light activated composite materials which provides some or all of the following features in combination: portability, light weight, inexpensive, little heat generation, no need for cooling system, no need for complicated circuitry, and novel semiconductor laser and LED light sources.
Each of the foregoing references is hereby incorporated by reference for the material disclosed therein.